1976 — May 11, HAZMAT tank truck hits I-610 ramp rail, falls onto SW Freeway, Houston, TX-6

— 6 NTSB. HAR. Transport Co…TX Tractor-Semitrailer…Collision…Houston…May 11, 1976.

Narrative Information

National Transportation Safety Board: “Synopsis

“About 11:08 a.m., on May 11, 1976, a Transport Company of Texas tractor-semitrailer (tank) transporting 7,509 gallons of anhydrous ammonia struck and penetrated a bridge rail on a ramp connecting I-610 with the Southwest Freeway (U.S. 59) in Houston, Texas. The tractor and trailer left the ramp, struck a support column of an overpass, and fell onto the Southwest Freeway, approximately 15 feet below. The anhydrous ammonia was released from the damaged tank semitrailer.

”Six persons died as a result of the accident, 78 persons were hospitalized, and approximately 100 other persons were treated for injuries.

“The National Transportation Safety Board determines that the probable cause of this accident was the excessive speed of the vehicle combined with the lateral surge of liquid in the partially loaded tank truck, which caused it to overturn. The cause of 5 of the 6 fatalities and all of the 178 injuries was the inhalation of anhydrous ammonia. Contributing to the severity of the accident was the failure of the bridge rail to contain or redirect the vehicle.

“Innovations in transportation of pressurized liquefied products could result in a reduction of accident severity. As a result of its investigation of another tank-semitrailer accident near Eagle Pass, Texas, on April 29, 1975, the Safety Board recommended that the Secretary of Transportation “initiate a research program to identify new approaches to reduce the injuries and damages caused by the dangerous behavior of pressurized, liquefied flammable gases released from breached tanks on bulk transport vehicles.” The Department of Transportation now intends to contract for such a study, depending upon the availability of funds, sometime during FY 1977. Ammonia will be included in the study.

RECOMMENDATIONS

“As a result of its investigation of this accident the National Transportation Safety Board submitted the following recommendations to the Federal Highway Administration:

“Expedite past recommendations of the Safety Board regarding the adoption of standards for bridge barrier systems that require new installations to comply with performance standards.” (Class II, Priority Follow-up)(H-77-4)

“In consultation with State and local governments, establish highway design criteria for the selection, location, and placement of traffic barrier systems that will redirect and prevent penetration when struck by heavy vehicles. The criteria for preventing vehicle penetration should consider the human exposure to injury and the effects of hazardous cargo that could result from barrier penetration.” (Class II, Priority Follow-up) (H-77-5)

“Develop guidelines for local and State agencies to use in designating and periodically reviewing routes for the transportation of hazardous materials as a means of reducing injury and damage from accidents involving hazardous materials in their jurisdictions.” (Class II, Priority Follow-up) (I-77-1)

“As a result of its investigation of this accident the National Transportation Safety Board reiterates the following recommendations made after previous investigations:

to the Federal Highway Administration:

“The Bureau of Motor Carrier Safety (Federal Highway Administration) in cooperation with affected industries, as represented by the Tank Truck Technical Council, conduct an investigation designed to resolve the overturn stability problems created by liquid surging of partially loaded tank-truck combinations. The ultimate objective of such a research program should be the promulgation of Federal regulations to limit the effects of surge to a specific degree. Such regulations might be based on acceptable liquid cargo outage and/or dampening requirements, consistent with safe tank-truck operations.” (H-72-45)

to the U.S. Department of Transportation:

“Initiate a research program to identify new approaches to reduce the injuries and damages caused by the dangerous behavior of pressurized, liquefied flammable gases released from breached tanks on bulk transport vehicles.” (I-76-5)”

(NTSB. HAR. Transport Co…TX Tractor-Semitrailer…Collision…Houston…May 11, 1976.)

Newspaper

May 12, AP: “Houston (AP) – Federal and state authorities began an investigation today into the freeway crash and explosion of an ammonia carrying tank truck that killed four persons and injured some 200 others. The tank truck, carrying 19 tons of anhydrous ammonia, plunged off an overpass onto the freeway Tuesday, exploding on impact. Many automobiles became involved in the wreckage.

“Most of the injured were overcome by fumes. Many were released after treatment but Houston hospitals reported 68 persons remained hospitalized late Tuesday. At least seven were said to be critical.

“Witnesses said the truck failed to make a curve at the exit ramp onto Southwest Freeway and Loop 610 and plunged 15 feet to the pavement and exploded. A dense cloud of ammonia fumes billowed into the air, causing motorists to abandon their cars. Many residents and workers in the area near the site, one of the city’s busiest traffic interchanges, were forced to evacuated homes and offices for a time.

“Authorities said up to 20 vehicles were involved in the explosion. Some cars were knocked facing the direction from which they had been coming. Twisted metal and bits of glass were flung far beyond the grassy embankments along the freeway.

“The dead were identified as William Gregory Schmidt, 28, of Corpus Christi, driver of the tank truck; Gordon D. McAdams, 40, of Conroe, Tex.; George Henty Pearson, 33, of Sugar Land, Tex., and David Randall Whiteman, 48, of Houston.

“Schmidt’s truck was owned by Transport Co. of Texas and was hauling ammonia loaded by Tenneco Chemicals Inc.

“One body was thrown 120 feet from the north side of the road. Another lay on the opposite side, one was in a truck and one was sprawled on the roadway.

“The Texas Air Control Board [TACB] said it will conduct an exploratory investigation and the National Transportation Safety Board announced that a four man team from Washington will probe the accident. Lloyd Stewart, regional Chief of the TACB, said the toxic cloud of fumes turned vegetation brown in its path….

“The explosion caused no fire but split apart at its base one of the huge concrete columns that supports the superstructure of the top level of the loop….

“The four bodies reeked so badly with ammonia when they were brought to the Harris County Morgue that the morgue had to be evacuated for a time, Dr. Joseph A. Jachimczyk, county medical examiner said.” (Associated Press. “Freeway crash probe begins.” Wichita Falls Times, TX. 5-12-1976, pp. A1 and A3.)

Sources

Associated Press. “Freeway crash probe begins.” Wichita Falls Times, TX. 5-12-1976, p. 1. Accessed 10-10-2021 at: https://newspaperarchive.com/wichita-falls-times-may-12-1976-p-1/

National Transportation Safety Board. Highway Accident Report. Transport Company of Texas Tractor-Semitrailer (Tank) Collision With Bridge Column and Sudden Dispersal of Anhydrous Ammonia Cargo, I-610 at Southwest Freeway, Houston, Texas, May 11, 1976 (NTSB HAR-77/01; NTIS PB-268251). Washington, DC: NTSB, adopted April 14, 1977. Accessed at: http://www.ntsb.gov/publictn/1977/HAR7701.htm